Sway control unit

ABSTRACT

A sway control unit to be linked between a towing vehicle and a towed vehicle and providing a rotary frictional resistance to lateral weaving or swaying of the towed vehicle with respect to the towing vehicle, without adversely affecting free vertical or necessary horizontal angular displacement of the vehicles relative to one another.

United States Patent Hedgepeth [451 Jan..18,1972

[54] SWAY CONTROL UNIT [72] Inventor: Edward B. Hedgepeth, Salt LakeCity,

Utah

[73] Assignees: Clifton E. Hedgepeth; Royce Doyle Hedgepeth; Jetta V.Vincent, all of Salt Lake City, Utah part interest to each [22] Filed:Oct. 8, 1969 [2l] Appl.No.: 864,604

[52] US. Cl ..280/446 B [51] Int. Cl t I ..B60d 1/00 [58] Field ofSearch ..280/446.3, 446, 446 B [56] References Cited UNITED STATESPATENTS 9/1966 Waldie ..280/446 B Primary Examiner-Leo F riaglia Auorney- Br Deon Criddle [57] ABSTRACT A sway control unit to be linkedbetween a towing ehicle and a towed vehicle and providing a rotaryfrictional resistance lo lateral weaving or swaying of the towed vehiclewith respect to the towing vehicle, without adversely affecting freevertical or necessary horizontal angular displacement of the vehiclesrelative to one another.

8 Claims, 5 Drawing Figures mmmm FIG.2

FNVENTOR. EDWARD a. HEDGEPETH ATTORNEY BRIEFDESCRIPI'ION OF THEINVENTION It has long been recognized that there is a need for means toretard or prevent the lateral swaying of a towed vehicle, such as atrailer, with respect to a towed vehicle. In the absence of such meansrough terrain, winding roads, crosswinds, or emergency stops, forexample, can all cause the towed vehicle to swing from side to sidebehind the towing vehicle. This may present a hazard to oncoming trafficand is particularly dangerous to the driver and occupants of the towingvehicle since it may cause the driver to lose control.

There have been a number of devices proposed in the past to provide swaycontrol. These have included hydraulic retarders, and mechanicalcontrols providing a reciprocating frictional resistance such as isdisclosed in U.S. Pat. No. 3,294,421 and in my copending application forU.S. Pat. Ser. No.'803,618, filed Mar. 3-, 1969, now U.S. Pat. No.3,531,139 and entitled ,lmproved Sway Control for Trailers. Many ofthese previously known devices are satisfactory if properly used, butothers are too costly or difficult to properly adjust to be widelyaccepted.

Objects of the present invention are to provide a reliable and low-costsway control unit that can be easily linked between a towing vehicle anda towed vehicle, regardless of the type hitch used to couple the twovehicles, and that will provide a positive push-or-pull forcetransmission through a retarderbrake to prevent lateral free swaying ofa towed vehicle with respect to a towingvehicle.

Other objects are to provide such a sway control unit wherein theretarder brake can be readily adjusted to preset the frictionalrestraint to sway of the towed vehicle and one that will not beadversely affected by ice, snow, rain or other weather conditions.

Still further objects are to provide a s'way control unit with aretarder brake that depends on a rotating friction force rather than areciprocating action and to greatly reduce the possibility of foreignmatter adversely affecting the frictional retardation of the unit.

Principal features of the unitinclude a rotational retarder brake unitwherein an adjustably compressed brake pad member and a cooperatingbrake plate member are placed in surface-to-surface engagement tofrictionally resist turning of a connected arm when the relative lateralpositions of a towed vehicle and a towing vehicle are changed. A rigidconnecting link is universally coupled between one of the vehicles andthe connected arm and the brake unit is fixed to the other vehicle. Thebrake pad is preferably made of a suitable elastomeric material having alimited degree of lubricity that will deform when compressed, andsurrounding members that prevent undesired expansion of the pad, providea protective cover for the pad and prevent inadvertant tightening of thefrictional resistance to the point where the towed vehicle will notproperly trail. A thrust bearing may be used to insure smooth rotationof the brake pad or plate, within the frictional resistance set on theunit, to prevent loosening of the adjustment means and to facilitatesetting of the adjustment means.

Other objects and features of the invention will become apparent fromthe following description and drawings.

THE DRAWINGS FIG. 1 is a top plan view of one preferred embodiment ofthe sway control unit of the invention, with the tongue of a towedvehicle and the towing support of a towing vehicle shown fragmentarily;

FIG. 2, a vertical view taken on the line 2-2 of FIG. 1;

FIG. 3, is a vertical sectional view taken on the line 33 of FIG. 1; v

FIG. 4 a vertical view taken on the line 4-4 of FIG. 1; and

F IG. 5, a view like that of FIG. 3, but showing the invention withanother form of retarder brake.

Referring now to the drawings:

In the illustrated preferred embodiment of FIGS. 1-4, the sway controlunit of the invention includes generally a retarder brake unit 10, shownmounted on a bifurcated trailer tongue 11, and a rigid link 12interconnecting the brake unit and a towing support 13 fixed to a towingvehicle, not shown. As will be apparent, while the brake unit is hereshown securely mounted on the tongue of the trailer or towed vehicle itcould as well be affixed on the towing vehicle and link 12 could then beused to interconnect the towed vehicle and the brake unit.

As shown, the brake unit 10 includes an L-shaped mounting bracket 14,one leg 14a of which is adapted to be mounted as by bolts 14b and nuts14c or by welding, or the like, to the trailer tongue 11. The other leg14d of bracket 14 then extends outwardly from the trailer tongue and theupper face thereof is formed as asupport plate. A pad 15 of suitabletough elastomeric material such as Adaprene" manufactured by the DupontCorporation is placed on the support plate and a ring 16 of metal orother sufficiently strong material is placed closely around the pad 15.

Ring 16 has a thickness somewhat'less than that of the uncompressed pad15 and the differential thickness will depend on the characteristics ofthe material from which pad is made. In any event, when the pad iscompressed tightly against plate 14d, as will be hereinafter more fullydescribed, ring 16 serves as a stop to limit the deformation and henceincreases the frictional engagement between the pad 15 and the plate 14dand a brake plate 17. By confining the material from which the pad ismade so that it will not flow out from between the support plate 14d anda brake plate 17, a desired frictional relationship can be set.

The circular, flat compression and brake plate 17 fits on top of pad 15and a thrust bearing assembly 18 is positioning on top of compressionand brake plate 17 and around a bushing 19 that surrounds a bolt 20.

Bolt 20 extends through the entire assembly and a nut 20a thereonsecures the assembly together and provides a means whereby thefrictional resistance developed between pad 15 and compression and brakeplate 17 can be preset as desired- An arm 21, fixed to and extendingoutwardly from plate 17 has an upstanding ball 22 fixed thereto toreceive socket 23 at one end of the link 12, the other end of which hasa socket 24 thereon adapted to fit on a ball 25 fixed to the towingsupport 13. The sockets 23 and 24 preferably have openings 23a and 24ain the top thereof, through which projections 22a and 25a of the balls22 and 25 respectively extend. The projections 22a and 25a have holesthercthrough and spring safety clips 26 and 27 are respectively insertedthrough. the holes to hold the sockets on the balls. The ball-and-socketcouplings provide universal connections between the link and the towingvehicle and the link and the brake unit so that the sway control unitdoes not in any way adverselyaffect vertical angular displacement of thevehicles relative to one another. At the same time the connections allowfor complete horizontal turning of the vehicles relative to one another,subject to the restraint imposed by the braking unit.

In operation, turning of either vehicle with respect to the other willcause rigid link 12 to either push-or-pull arm 19 and thereby rotateplate 17 with respect to the brake pad. The frictional engagementbetween the brake pad and plate 17 thus serves to resist free swingingor swaying movement of the towed vehicle with respect to the towingvehicle and forces the towed vehicle to stay more nearly behind thetowing vehicle except when a positive pushing or pulling force isapplied that is strong enough to overcome the frictional resistance.Alternatively. although not shown in the drawings, arm 21 couldalternatively be connected to ring 16, which in turn could he fixed tothe pad 15 to give the same frictional restraint.

- the arm 21 is secured.

Conventional thrust bearing assembly 18 includes an upper raceway 1311,a lower raceway 18b and rollers 18c therebetween. Nut 20a acts on upperraceway 18a through a washer 20b and the lower raceway rests on andturns with brake plate 17. The bearing assembly insures that plate 17will not be clamped so tightly by bolts 20 and nut 20a that it cannot beturned. At the same time, the bearing assembly allows movement of thebrake plate -without moving nut 20a and makes it easier to adjust thefrictional restraint since the nut can be more easily turned with theupper raceway 18a,

While coupling ball 22 is shown mounted on an arm 21 that extends outfrom plate 17 it should be apparent that the arm can be omitted and theball 22 can be fixed directly to plate 17. It is only necessary that theball 20 .be eccentrically mounted with respect to the opening of plate17 through which bolt 20 is inserted so that when a sufficiently largemoment force is created through relative turning of the vehicles theplate 17 is positively turned to the extent necessary for propertrailing of the towed vehicle.

As is shown in FIG. 5, the retarder brake unit can also utilize arelative rotational braking force between an upstanding cylindricalbrake pad 30 of suitable elastomeric material, such as Adaprene and asurrounding brake sleeve 31 to which Bolt 20 extends up through leg 14dof support plate 14 as previously described and pad 30 surrounds thebolt. Nut 20a is then-threaded onto the bolt to force a compressionplate 32 against the pad 30, which extends upwardly above sleeve 31.

This expands the elastomeric pad against the inner wall of sleeve 31,thereby increasing thefrictional resistance between them. If desired, athrust bearing like that shown in FIGS. 1-4 can be used beneath the nut20a and the compression plate 31 to facilitate frictional adjustment, aspreviously described.

If the inner wall of sleeve 31 is notched or grooved, as shown at 33,the pad 30 will be deformed into the notches or grooves to provide aneven greater resistance to relative movement between the sleeve and thepad when nut 20a is tightened on bolt 20. In either embodiment of theinvention, the retarder brake pad can be allowed to slide freely withrespect to the support plate 14d or the plate 14d can have grooves ornotches therein as shown at 34 in FIG. 5, or be otherwise provided withirregularities into which the pad will deform when it is compressed. Theresistance to turning of the pad with respect to the support plate canthus be greatly increased. While not shown in the embodiment of FIGS.1-4, it should be apparent that similar notches, grooves orirregularities can be provided in the surface of brake plate 17 inengagement with the brake pad. Whether or not such structure is usedwill be dependent on such factors as the resistance to turning that isdesired and the nature of the materials that are used.

Materials other than Adaprene can be used as the brake pad, but becauseof its durability, resistance to weathering, and limited lubricity, evenunder compression, this has been found to be an ideally suitablematerial.

Other changes and modifications, within the scope of the followingclaims, will be obvious to those skilled in the art.

We claim:

1. A sway control unit for connection between a towed vehicle and atowing vehicle comprising a retarder brake unit adapted to be fixed toone of said vehicles and including a brake pad member, a brake platemember, a support plate beneath the brake pad arranged such that thebrake plate member is positioned above the pad and adjustable means forclamping said bearing assembly, brake plate member, brake pad member andsupport plate together, whereby a desired frictional engagement can beprovided between the brake pad and the brake plate during rotation ofone of them with respect to the other about a common central axis;

a thrust bearing between said clamping means and said brake plate;

a rigid link;

means for universally coupling one end of said link to the othervehicle; and

means for universally coupling the other end of said link to one of saidmembers at a point spaced from the said central axis.

2. A sway control unit for connection between a towed vehicle and atowing vehicle comprising a retarder brake unit adapted to be fixed toone of said vehicles and including a brake pad member, a brake platemember, a support plate having an irregular pad-engaging surface beneaththe brake pad arranged such that the brake plate member is positionedabove the pad and adjustable means for clamping said bearing assembly,brake plate member, brake pad member and support plate together, wherebythe pad is deformed into the irregularities of the pad-engaging surfaceand a desired frictional engagement can be provided between the brakepad and the brake plate during rotation of one of them with respect tothe other about a common central axis;

a rigid link;

means for universally coupling one end of said link to the othervehicle; and

means for universally coupling the other end of said link to one of saidmembers at a point spaced from the said central axis.

3. A sway control unit for connection between a towed vehicle and atowing vehicle comprising a retarder brake unit adapted to be fixed toone of said vehicles and including a brake pad member, a support plate,a cylindrical brake plate member extending around the pad, above thesupport plate, with the pad extending above the brakeplate, acompression plate on the pad above the brake plate, and adjustable meansfor clamping the pad between the support plate and the compressionplate, whereby the pad may be expanded into preset frictional engagementwith the brake plate and whereby one of said members is rotatable withrespect to the other about a common axis;

a rigid link;

means for universally coupling one end of said link to the othervehicle; and

means for universally coupling the other end of said link to one of saidmembers at a point spaced from the said common axis.

4. A sway control unit as in claim 3, wherein the inner surface of thebrake plate is irregular and the brake pad is deformable into theirregularities thereof.

5. A sway control unit as in claim 3, wherein the pad-engaging surfaceof the support plate is irregular and the pad is deformable into theirregularities thereof.

6. A sway control unit for connection between a towed vehicle and atowing vehicle comprising a retarder brake unit adapted to be fixed toone of said vehicles and including a brake pad member having apad-engaging surface formed irregular, whereby the pad is deformableinto the irregularities thereof, and a brake plate member and means forclamping said brake pad member and brake plate member together in asurface-tosurface relationship whereby one of them is rotatable withrespect to the other about a common central axis;

a rigid link;

means for universally coupling one end of said link to the othervehicle; and

means for universally coupling the other end of said link to one of saidmembers at a point spaced from the said central axis.

7. A sway control unit for connection between a towed vehicle and atowing vehicle comprising a retarder brake unit adapted to be fixed toone of said vehicles and including a brake pad member and a brake platemember and means for clamping said brake pad member and brake platemember together in a surface-to-surface relationship whereby one of themis rotatable with respect to the other about a common central axis;

arigid link; and

means for universally coupling the rigid link comprising a socket ateach end of the link having a hole centrally through the top thereof,

a ball fixed to each vehicle and having a projection thereon adapted toextend through a hole in the socket when the ball is in the socket, saidprojections each having holes therethrough, and

spring clips adapted to be inserted through the holes in the projectionsand to be held therein, whereby the sockets cannot be removed from theballs until the spring clips have been removed from the holes throughthe projectrons.

Q. A sway control unit for connection between a towed vehicle and atowing vehicle comprising means for universally coupling the otherend ofsaid link to one of said members at a point spaced from the said centralaxis.

t l t W l

1. A sway control unit for connection between a towed vehicle and a towing vehicle comprising a retarder brake unit adapted to be fixed to one of said vehicles and including a brake pad member, a brake plate member, a support plate beneath the brake pad arranged such that the brake plate member is positioned above the pad and adjustable means for clamping said bearing assembly, brake plate member, brake pad member and support plate together, whereby a desired frictional engagement can be provided between the brake pad and the brake plate during rotation of one of them with respect to the other about a common central axis; a thrust bearing between said clamping means and said brake plate; a rigid link; means for universally coupling one end of said link to the other vehicle; and means for universally coupling the other end of said link to one of said members at a point spaced from the said central axis.
 2. A sway control unit for connection between a towed vehicle and a towing vehicle comprising a retarder brake unit adapted to be fixed to one of said vehicles and including a brake pad member, a brake plate member, a support plate having an irregular pad-engaging surface beneath the brake pad arranged such that the brake plate member is positioned above the pad and adjustable means for clamping said bearing assembly, brake plate member, brake pad member and support plate together, whereby the pad is deformed into the irregularities of the pad-engaging surface and a desired frictional engagement can be provided between the brake pad and the brake plate during rotation of one of them with respect to the other about a common central axis; a rigid link; means for universally coupling one end of said link to the other vehicle; and means for universally coupling the other end of said link to one of said members at a point spaced from the said central axis.
 3. A sway control unit for connection between a towed vehicle and a towing vehicle comprising a retarder brake unit adapted to be fixed to one of said vehicles and including a brake pad member, a support plate, a cylindrical brake plate member extending around the pad, above the support plate, with the pad extending above the brake plate, a compression plate on the pad above the brake plate, and adjustable means for clamping the pad between the support plate and the compression plate, whereby the pad may be expanded into preset frictional engagement with the brake plate and whereby one of said members is rotatable with respect to the other about a common axis; a rigid link; means for universally coupling one end of said link to the other vehicle; and means for universally coupling the other end of said link to one of said members at a point spaced from the said common axis.
 4. A sway control unit as in claim 3, wherein the inner surface of the brake plate is irregular and the brake pad is deformable into the irregularities thereof.
 5. A sway control unit as in claim 3, wherein the pad-engaging surface of the support plate is irregular and the pad is deformable into the irregularities thereof.
 6. A sway control unit for connection between a towed vehicle and a towing vehicle comprising a retarder brake unit adapted to be fixed to one of said vehicles and including a brake pad member having a pad-engaging surface formed irregular, whereby the pad is deformable into the irregularities thereof, and a brake plate member and means for clamping said brake pad member and brake plaTe member together in a surface-to-surface relationship whereby one of them is rotatable with respect to the other about a common central axis; a rigid link; means for universally coupling one end of said link to the other vehicle; and means for universally coupling the other end of said link to one of said members at a point spaced from the said central axis.
 7. A sway control unit for connection between a towed vehicle and a towing vehicle comprising a retarder brake unit adapted to be fixed to one of said vehicles and including a brake pad member and a brake plate member and means for clamping said brake pad member and brake plate member together in a surface-to-surface relationship whereby one of them is rotatable with respect to the other about a common central axis; a rigid link; and means for universally coupling the rigid link comprising a socket at each end of the link having a hole centrally through the top thereof, a ball fixed to each vehicle and having a projection thereon adapted to extend through a hole in the socket when the ball is in the socket, said projections each having holes therethrough, and spring clips adapted to be inserted through the holes in the projections and to be held therein, whereby the sockets cannot be removed from the balls until the spring clips have been removed from the holes through the projections.
 8. A sway control unit for connection between a towed vehicle and a towing vehicle comprising a retarder brake unit adapted to be fixed to one of said vehicles and including a brake pad member and a brake plate member and means for clamping said brake pad member and brake plate member together in a surface-to-surface relationship whereby one of them is rotatable with respect to the other about a common central axis; a thrust bearing between said clamping means and said brake plate; a rigid link; means for universally coupling one end of said link to the other vehicle; and means for universally coupling the other end of said link to one of said members at a point spaced from the said central axis. 